This invention relates to a process for the production of a pressure container from a fiber-reinforced synthetic resin material, consisting of a wound-coil structure having opposite polar openings of different sizes and connecting elements integrated therein at both ends, the coiled structure being produced by applying to the shaping core or mandrel mounted on the winding shaft of a winding machine, under determined winding angles, reinforcing fibers impregnated with a hardenable synthetic resin (pre-polymerizate); the assembled structure is then fully hardened by heating and cooled down after hardening is complete. The invention further relates to a synthetic resin container produced by this process, comprising a fiber-reinforced structure.
In the manufacture of aircraft and motor vehicles, where light weight and a high stress resistance are of importance, synthetic resin pipes and containers which are fiber-reinforced are being increasingly used. These pipes and containers are usually provided at their ends with connecting elements which are referred to as "fittings". The attachment of such elements which are often subject to high stresses, to a fiber-reinforced structure such as a container or pipe frequently causes certain often major problems, e.g., leakage or peeling from fittings.
In manufacturing fiber-reinforced, wound-up synthetic resin containers, the fibers are wound about a shaping core on a shaft of a winding machine, with predetermined winding angles which are adjusted to the demands of mechanical strength and shape made upon the final product.
The smallest winding angle w of a cross winding made by geodetic depositing of fibers in a polar, i.e. an end region, of a container, can be calculated with the help of the equation EQU sin (w)=d/D
wherein d is the polar diameter (e.g. the diameter of the opening at a narrow end of the container), at which the direction in which the windings are laid on the core is altered, and D is the diameter of the cylindrical portion of the container.
In important kinds of use, the "fittings" to be connected to the preferably open ends of a container are usually of different polar diameter. If the joint between container ends and the connected fittings is subject to high mechanical stresses, a geodetic deposition of the fibers should be used. However, such deposition conforming with the above equation requires that the polar openings of the container are of equal size.